1. Field of the Invention
The present invention relates to an active sound control apparatus for generating a sound effect based on a vibratory noise source signal representative of information of a running state of a vehicle or an operating state of an engine.
2. Description of the Related Art
There has been known an active sound control apparatus (hereinafter referred to as “ASC apparatus”) as one of the apparatus for controlling the acoustic properties in a vehicle's passenger compartment in relation to noise therein.
The ASC apparatus generates a sound effect in synchronism with the noise to increase the acoustic effect in the passenger compartment by highlighting a change in the speed of the vehicle. Specifically, the ASC apparatus outputs a sound effect from speakers for creating a live sound atmosphere in the passenger compartment, using control parameters including the degree of a reference signal of harmonics based on an engine rotational speed [rpm], the engine rotational speed, a vehicle speed change [km/hour/second], etc (see, for example, U.S. Patent Application Publication No. 2006/0215846).
However, the invention of U.S. Patent Application Publication No. 2006/0215846 still remains to be improved for enhancing the live sound atmosphere in the passenger compartment.